Remove the implicit conversion from int64 to XRPAmount. The motivation for this
was noticing that many calls to `to_string` with an integer parameter type were
calling the wrong `to_string` function. Since the calls were not prefixed with
`std::`, and there is no ADL to call `std::to_string`, this was converting the
int to an `XRPAmount` and calling `to_string(XRPAmount)`.
Since `to_string(XRPAmount)` did the same thing as `to_string(int)` this error
went undetected.
At this point all of the jss::* names are defined in the same
file. That file has been named JsonFields.h. That file name
has little to do with either JsonStaticStrings (which is what
jss is short for) or with jss. The file is renamed to jss.h
so the file name better reflects what the file contains.
All includes of that file are fixed. A few include order
issues are tidied up along the way.
Add envconfig test helper for manipulating Env config via
callables. Create new common modifiers for non-admin config,
validator config and one for using different server port values.